October Antitrust and Competition Bulletin: Top-of-Mind Global Antitrust Issues

Welcome to this edition of the Sidley Antitrust and Competition Bulletin — thoughts on topics that are top of mind for Sidley’s global Antitrust and Competition team and why they may matter to you.

• California passes new antitrust legislation regarding pricing algorithms and enhancing penalties for violations of California’s antitrust laws.
• The EU and UK revise “safe harbor” rules for technology transfer agreements.
• The Court of Justice of the European Union (CJEU) confirms that limitation period starts only once a national competition authority decision is final.
• Antitrust merger review continues, but litigation pauses under the U.S. government shutdown.
• The Federal Trade Commission (FTC) sues Zillow and Redfin based on partnership agreement and alleged failure to file a Hart-Scott-Rodino (HSR) form.

Read more on how this news can affect your business below....

Gavin Newsom Signs California Antitrust Legislation: This month, Gavin Newsom, California’s Democratic governor , signed Assembly Bill 325 (AB 325), which prohibits (1) agreements to use a “common pricing algorithm” to harm competition and (2) the use or distribution of a common pricing algorithm if one person “coerces” another person to use it “for the same or similar products” in California. He also signed Senate Bill 763 (SB 763), which increases criminal penalties faced by corporations and individuals convicted of violating California’s Cartwright Act. SB 763 increases criminal penalties for corporations from $1 million to $6 million per violation and from $250,000 to $1 million per violation for individuals. The statute also creates an entirely new civil penalty regime — independent of and in addition to the criminal penalties — of up to $1 million “per violation” in actions brought either by the California Attorney General or a California district attorney.

Why it matters: Antitrust legislation and case law related to the use of a pricing algorithm are continuing to develop, as are the consequences for violating the antitrust laws (including at the state level). As your business considers its policies and practices related to the use of pricing algorithms, consider contacting antitrust counsel for the latest thinking and advice tailored to your business.

EU and UK revise “safe harbor” rules for technology transfer agreements: On September 11, the European Commission (EC) published draft revisions to the Technology Transfer Block Exemption Regulation and its Guidelines, ahead of their expiration in April 2026. The public consultation ran until October 23, with final adoption expected in early 2026. Key updates:

• flexible market-share calculations — allowing a three-year average, treating new technologies with no sales as having zero market share, and extending the grace period to three years
• strengthened “soft safe harbor” conditions for technology pools, requiring essentiality and transparency safeguards to prevent “double dipping”
• new sections outlining “soft safe harbor” criteria for licensing negotiation groups and providing guidance on data licensing agreements

Meanwhile, the UK Competition and Markets Authority proposed a Technology Transfer Block Exemption Order mirroring the EU regime while introducing an alternative “three-or-more competing technologies” test for safe-harbor protection.

Why it matters: The parallel EU and UK reviews reflect efforts to modernize technology transfer rules while maintaining consistency across jurisdictions. Any divergence between the two regimes may affect cross-border licensing and compliance strategies, making the 2026 transition a key moment for assessing practical implications and proactive alignment. For more information, see our Sidley Update.

CJEU confirms that the limitation period to file a follow-on action starts only once a decision of a national competition authority (NCA) is final: The CJEU has clarified that the limitation period for follow-on actions based on a decision of a NCA starts only once that decision becomes final. The defendant in a national case argued that the Spanish one-year limitation period had begun upon publication of the Spanish Competition Authority’s 2015 infringement decision. In its preliminary ruling, the CJEU rejected this position, instead finding that claimants cannot be expected to act before a decision is legally binding and publicly accessible in its final form.

Why it matters: Different limitation periods for follow-on competition damages claims will apply depending on whether the claim is based on an EC decision or an NCA decision. Unlike EC decisions, which are binding upon the publication of the summary decision in the Official Journal of the European Union, the limitation period for actions based on decisions of NCAs start once that decision becomes final and publicly accessible as defined under national law.

Antitrust regulation during the shutdown: On October 1, much of the U.S. government closed because of a lapse in appropriations. It remains shut down as of this writing, the second-longest shutdown in U.S. history. The impact has been felt both at the agencies and in government-led antitrust litigation. The FTC immediately suspended its ordinary day-to-day operations and began furloughs of most employees. During the shutdown, the government has continued to accept HSR merger filings; however, the Premerger Notification Office (PNO) will not respond to questions or requests for information from outside parties. It remains to be seen in the days ahead whether any deals will receive second requests extending the regulatory review of mergers during a shutdown. On the litigation front, the FTC has suspended all nonmerger investigations except where necessary to prevent a statute of limitations from running or to meet court deadlines. Similarly, and also relevant to the Department of Justice (DOJ), a number of federal district courts — including the Southern District of New York, the Northern District of California, and the Northern District of Illinois — have temporarily stayed civil cases involving government parties, though at least one court (the District Court of Maryland) bucked the trend and denied a stay, despite the lapse in funding. Even the District of Maryland will soon run out of funds if it has not already by the time of publication.

Why it matters: This is the third government shutdown resulting from failed negotiations between President Donald Trump and congressional Republicans and Democrats and so offers insight as to how antitrust regulation will proceed if there is a fourth. In the days ahead, if the shutdown continues, we will begin to see whether the furloughs at FTC and DOJ mean that deals that might have faced a second request will not — with the concomitant downstream possibility of postclosing investigations — or whether deals that would not otherwise have expected to receive a second request will in order to extend the HSR waiting period for transactions.

FTC sues Zillow and Redfin based on partnership agreement and failure to file an HSR form: On September 30 (the day before the government shutdown), the FTC filed a complaint against Zillow and Redfin alleging that the parties violated the antitrust laws by illegally agreeing to remove Redfin from the online rentals marketplace (referred to as Internet Listing Services or ILSs), eliminating a significant competitor to Zillow. Zillow and Redfin allegedly agreed that Zillow would pay Redfin $100 million in exchange for Redfin’s agreement “to stop selling multifamily advertising, to terminate its existing multifamily advertising contracts, and to transition those customers to Zillow.” Redfin subsequently terminated its ILS employees, helped Zillow hire them, and turned over sensitive business information so Zillow could transition Redfin’s customers to Zillow. Now Redfin’s ILS websites are syndicators of Zillow listings.

Why it matters: The FTC claims the partnership between Zillow and Redfin amounts to Zillow’s paying off a competitor to stop competing. This complaint shows that the Trump administration is still bringing enforcement actions against allegedly anticompetitive conduct. In addition, the FTC claims Zillow’s acquisition of Redfin assets constituted an unlawful acquisition in violation of Section 7 of the Clayton Act, which could independently require the parties to unwind their transaction and pay penalties up to $53,088 per day — even if their agreement is ultimately deemed legal. This case is an important reminder that partnership agreements can trigger an HSR filing requirement and should always be closely examined by antitrust counsel.